title: Determination of insulin-like growth factor-I reference values using an immunoradiometric assay in a Brazilian adult population.
abstract: BACKGROUND
  Serum levels of total insulin-like growth factor I (IGF-I) reflect endogenous growth hormone (GH) secretion in healthy adults, which makes it a good diagnostic marker for screening of GH-related disorders. Studies also have supported a possible relation between IGF-I levels and the risk and prognostic for some malignancies, besides a relation between IGF-I levels and mortality.
  
  
  OBJECTIVE
  As the determination of the IGF-I normal values for local populations is strongly desired, the aim of this investigation was to determine reference values for IGF-I using an immunoradiometric assay (IRMA) in an adult Brazilian population of Rio de Janeiro city, since there is no other study using this methodology in Brazilian population, and that this method is widely used in Brazil and worldwide.
  
  
  METHODS
  The study included samples of blood taken from 484 healthy subjects (251 men and 233 women) aged 18-70. The subjects agreed with this study, approved by the Ethical Committee of the Instituto Estadual de Hematologia Arthur de Siqueira Cavalcanti, Rio de Janeiro, Brazil. The samples were analyzed using a Diagnostic System Laboratories kit. For data analysis, age- and sex-specific figures were fitted after transformation of IGF-I values.
  
  
  RESULTS
  In adulthood, a slow age-dependent decrease was found. There was no significant difference in IGF-I values between men and women.
  
  
  CONCLUSIONS
  This study established age-specific IGF-I reference values, for a healthy Brazilian adult population, determined by a widely IGF-I, IRMA used currently in Brazil.
authors.affiliation: Instituto de Estadual de Diabetes e Endocrinologia Luiz Capriglione, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Denise B
authors.initials: DB
authors.lastname: Leite
authors.forename: Ricardo M R
authors.initials: RM
authors.lastname: Meirelles
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Mandarim-De-Lacerda
authors.forename: Haroldo J
authors.initials: HJ
authors.lastname: Matos
authors.forename: Sebastião D
authors.initials: SD
authors.lastname: Santos-Filho
authors.forename: Mario
authors.initials: M
authors.lastname: Bernardo-Filho
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001938:Brazil; D002624:Chemistry, Clinical / Q000592:standards*; D005260:Female; D006801:Humans; D015592:Immunoradiometric Assay / Q000592:standards*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011933:Reagent Kits, Diagnostic / Q000592:standards*; D012016:Reference Values; D055815:Young Adult
chemical_list: D011933:Reagent Kits, Diagnostic; D007334:Insulin-Like Growth Factor I